Author: alc
Date: Wed Sep 18 07:01:01 2019
New Revision: 352469
URL: https://svnweb.freebsd.org/changeset/base/352469
Log:
MFC r350347
Implement pmap_advise(). (Without a working pmap_advise() implementation
madvise(MADV_DONTNEED) and madvise(MADV_FREE) are NOPs.)
Modified:
stable/12/sys/arm64/arm64/pmap.c
Directory Properties:
stable/12/ (props changed)
Modified: stable/12/sys/arm64/arm64/pmap.c
==============================================================================
--- stable/12/sys/arm64/arm64/pmap.c Wed Sep 18 06:50:29 2019
(r352468)
+++ stable/12/sys/arm64/arm64/pmap.c Wed Sep 18 07:01:01 2019
(r352469)
@@ -2493,7 +2493,7 @@ pmap_remove_l2(pmap_t pmap, pt_entry_t *l2, vm_offset_
/*
* pmap_remove_l3: do the things to unmap a page in a process
*/
-static int __unused
+static int
pmap_remove_l3(pmap_t pmap, pt_entry_t *l3, vm_offset_t va,
pd_entry_t l2e, struct spglist *free, struct rwlock **lockp)
{
@@ -4833,6 +4833,110 @@ out:
void
pmap_advise(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, int advice)
{
+ struct rwlock *lock;
+ vm_offset_t va, va_next;
+ vm_page_t m;
+ pd_entry_t *l0, *l1, *l2, oldl2;
+ pt_entry_t *l3, oldl3;
+
+ if (advice != MADV_DONTNEED && advice != MADV_FREE)
+ return;
+
+ PMAP_LOCK(pmap);
+ for (; sva < eva; sva = va_next) {
+ l0 = pmap_l0(pmap, sva);
+ if (pmap_load(l0) == 0) {
+ va_next = (sva + L0_SIZE) & ~L0_OFFSET;
+ if (va_next < sva)
+ va_next = eva;
+ continue;
+ }
+ l1 = pmap_l0_to_l1(l0, sva);
+ if (pmap_load(l1) == 0) {
+ va_next = (sva + L1_SIZE) & ~L1_OFFSET;
+ if (va_next < sva)
+ va_next = eva;
+ continue;
+ }
+ va_next = (sva + L2_SIZE) & ~L2_OFFSET;
+ if (va_next < sva)
+ va_next = eva;
+ l2 = pmap_l1_to_l2(l1, sva);
+ oldl2 = pmap_load(l2);
+ if (oldl2 == 0)
+ continue;
+ if ((oldl2 & ATTR_DESCR_MASK) == L2_BLOCK) {
+ if ((oldl2 & ATTR_SW_MANAGED) == 0)
+ continue;
+ lock = NULL;
+ if (!pmap_demote_l2_locked(pmap, l2, sva, &lock)) {
+ if (lock != NULL)
+ rw_wunlock(lock);
+
+ /*
+ * The 2MB page mapping was destroyed.
+ */
+ continue;
+ }
+
+ /*
+ * Unless the page mappings are wired, remove the
+ * mapping to a single page so that a subsequent
+ * access may repromote. Since the underlying page
+ * table page is fully populated, this removal never
+ * frees a page table page.
+ */
+ if ((oldl2 & ATTR_SW_WIRED) == 0) {
+ l3 = pmap_l2_to_l3(l2, sva);
+ KASSERT(pmap_load(l3) != 0,
+ ("pmap_advise: invalid PTE"));
+ pmap_remove_l3(pmap, l3, sva, pmap_load(l2),
+ NULL, &lock);
+ }
+ if (lock != NULL)
+ rw_wunlock(lock);
+ }
+ KASSERT((pmap_load(l2) & ATTR_DESCR_MASK) == L2_TABLE,
+ ("pmap_advise: invalid L2 entry after demotion"));
+ if (va_next > eva)
+ va_next = eva;
+ va = va_next;
+ for (l3 = pmap_l2_to_l3(l2, sva); sva != va_next; l3++,
+ sva += L3_SIZE) {
+ oldl3 = pmap_load(l3);
+ if ((oldl3 & (ATTR_SW_MANAGED | ATTR_DESCR_MASK)) !=
+ (ATTR_SW_MANAGED | L3_PAGE))
+ goto maybe_invlrng;
+ else if (pmap_pte_dirty(oldl3)) {
+ if (advice == MADV_DONTNEED) {
+ /*
+ * Future calls to pmap_is_modified()
+ * can be avoided by making the page
+ * dirty now.
+ */
+ m = PHYS_TO_VM_PAGE(oldl3 & ~ATTR_MASK);
+ vm_page_dirty(m);
+ }
+ while (!atomic_fcmpset_long(l3, &oldl3,
+ (oldl3 & ~ATTR_AF) | ATTR_AP(ATTR_AP_RO)))
+ cpu_spinwait();
+ } else if ((oldl3 & ATTR_AF) != 0)
+ pmap_clear_bits(l3, ATTR_AF);
+ else
+ goto maybe_invlrng;
+ if (va == va_next)
+ va = sva;
+ continue;
+maybe_invlrng:
+ if (va != va_next) {
+ pmap_invalidate_range(pmap, va, sva);
+ va = va_next;
+ }
+ }
+ if (va != va_next)
+ pmap_invalidate_range(pmap, va, sva);
+ }
+ PMAP_UNLOCK(pmap);
}
/*
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